Miami—The use of probiotics during the prenatal period and early in infants’ lives appears to have some benefits, but those do not include protection against asthma and wheezing.

The study, led by researchers from the University of Miami, suggests that probiotics might reduce immunoglobulin E (IgE) levels in infants and protect against sensitization to hereditary allergies. The report was published recently in the journal Pediatrics.

Some past research has indicated that probiotics could reduce the risk of atopy and asthma in children, but results have been conflicting and some of the studies have not been large enough to have significance, according to background in the article.

In response, the authors performed a meta-analysis of randomized, placebo-controlled trials to assess the effects of probiotic supplementation on atopic sensitization and asthma/wheeze prevention in children. They looked at 1,081 randomized trials published between 2001 and 2012, identifying 25 with 4,031 participants for inclusion.

They found that probiotics were effective in reducing total immunoglobulin E (IgE) (mean reduction: -7.59 U/mL [95% confidence interval (CI): -14.96 to -0.22]; P = .044), with meta-regression indicating that the reduction in IgE was more pronounced with longer follow-up.

In addition, probiotics were found to significantly reduce the risk of atopic sensitization when administered prenatally (relative risk: 0.88 [95% CI: 0.78 to 0.99]; P = .035 for positive result on the skin prick test and/or elevated specific IgE to common allergens) and postnatally (relative risk: 0.86 [95% CI: 0.75 to 0.98]; P = .027 for positive result on skin prick test). Lactobacillus acidophilus, compared with other strains, was associated with an increased risk of atopic sensitization (P = .002).

On the other hand, the researchers found that probiotics did not significantly reduce asthma/wheeze (relative risk: 0.96 [95% CI: 0.85 to 1.07]).

“Prenatal and/or early-life probiotic administration reduces the risk of atopic sensitization and decreases the total IgE level in children but may not reduce the risk of asthma/wheeze,” the authors conclude. “Follow-up duration and strain significantly modified these effects. Future trials for asthma prevention should carefully select probiotic strain and consider longer follow-up.”